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Publications

Publications by SYSTEM

2020

A multi objective approach for DRT service using tabu search

Authors
Torgal, M; Dias, TG; Fontes, T;

Publication
Transportation Research Procedia

Abstract
Urban population is increasing fast. This is creating new challenges to public transport systems since some groups of citizens as elderly people may have sensory, cognitive or motor impairments that need to be addressed. This work explores the potential of a Demand Responsive Transport (DRT) system for people with reduced mobility in an urban environment. For this purpose, the Dial-A-Ride Problem (DARP) was implemented using a multivariable minimisation approach. In this approach, an Assigning Request to Vehicles (ARV) algorithm is used to obtain an initial solution. Then a Multi-Objective Tabu Search Algorithm (MOTSA) is applied to the initial solution to search for the non-dominated solution (optimisation phase). In this optimisation phase, the total travelled distance, the deadheading distance and the number of vehicles were minimised. The performance of the model was computed combining different parameters' values of the number of requests, boarding time for each user, the number of seats in each vehicle, vehicle's speed, the total number of iterations, and candidate threshold number (the algorithm's parameter). The computational results found a strong positive correlation between the number of requests and the: total travelled distance (rs = 0.977, p-value<0.001) and the number of vehicles (rs =0.883, p-value<0.001); and a low positive correlation between the number of requests and the optimised total travelled distance (rs =0.331, p-value<0.001) and the optimised number of vehicles (rs =0.340, p-value<0.001). © 2020 The Authors. Published by ELSEVIER B.V.

2020

Understanding mobility patterns and user activities from geo-tagged social networks data

Authors
Carvalho, AM; Ferreira, MC; Dias, TG;

Publication
Transportation Research Procedia

Abstract
Social networks are strongly present in the daily life of modern society. Most people use these social networks to share information about their lives, their opinions, places they visit and their state of mind. Generally, these posts are composed of various information, being the location of the users location part of the data. The purpose of this work is to obtain the location of the posts and observe the users mobility pattern in the city of Porto, Portugal. This paper discusses the technologies available for obtaining the data, the social networks currently worth studying and their respective restrictions. It also explores new approaches to collect the data from the desired social networks, respecting all restrictions currently applied. The different software solutions developed for the social networks interactions are explored and described in depth. Subsequently, the necessary software for social networks is reviewed, the possible algorithms for data mining are discussed and its implementation is presented. Finally, the results obtained are interpreted and studied according to the characteristics of the city, tourism promotions and transport routes. © 2020 The Authors. Published by ELSEVIER B.V.

2020

A Survey of Mobile Ticketing Services in Urban Mobility Systems

Authors
Ferreira, MC; Dias, TG; Falcão e Cunha, J;

Publication
International Journal of Smart Sensor Technologies and Applications

Abstract
Modern mobile ticketing service solutions facilitate access to mobility services and free customers from difficult purchasing decisions. However, implementing these solutions is complex, as they involve many different stakeholders, with sometimes conflicting interests. This paper presents a survey of mobile ticketing services in the urban mobility context. It starts by defining mobile ticketing and explores the different electronic ticket schemes that are being implemented around the world, as well as the most used technologies to provide the service. Then, it addresses the complex mobile ticketing ecosystem, identifying the main actors involved, their motivations, and concerns. This allows the authors to define their role and contribution to the mobile ticketing ecosystem. Finally, the paper presents future trends and research directions related to mobile ticketing services, being a valuable guide for researchers and practitioners.

2020

Prediction of academic dropout in a higher education institution using data mining [Previsão do abandono académico numa instituição de ensino superior com recurso a data mining]

Authors
Martins, MPG; Migueis, VL; Fonseca, DSB; Gouveia, PDF;

Publication
RISTI - Revista Iberica de Sistemas e Tecnologias de Informacao

Abstract
This study proposes two predictive models of classification that allow to identify, at the end of the 1st and 2nd semesters, the undergraduate students of a higher education institution more prone to academic dropout. The proposed methodology, which combines 3 popular data mining algorithms, such as random forest, support vector machines and artificial neural networks, in addition to contributing to predictive performance, allows to identify the main factors behind academic dropout. The empirical results show that it is possible to reduce to about 1/4 the 4 tens potential predictors of dropout, and show that there are essentially two predictors, concerning student’s curriculum context, that explain this propensity. This knowledge is useful for decision-makers to adopt the most appropriate strategic measures and decisions in order to reduce student dropout rates.

2020

Quality Assurance of Doctoral Education: Current Trends and Future Developments

Authors
Cardoso, S; Rosa, MJ; Miguéis, V;

Publication
Structural and Institutional Transformations in Doctoral Education

Abstract

2020

Predicting Market Basket Additions as a Way to Enhance Customer Service Levels

Authors
Migueis, VL; Teixeira, R;

Publication
EXPLORING SERVICE SCIENCE (IESS 2020)

Abstract
It is imperative that online companies have a complete in-depth understanding of online behavior in order to provide a better service to their customers. This paper proposes a model for real-time basket addition in the e-grocery sector that includes predictors inferred from anonymous clickstream data, such as a Markov page view sequence discrimination value. This model aims at anticipating the addition and the non-addition of items to customers' market basket, in order to enable marketers to act conveniently, for example recommending more appropriate items. Two classification techniques are used in the empirical study: logistic regression and random forests. A real sample of anonymous clickstream data taken from the servers of a European e-retailing company is explored. The empirical results reveal the high predictive power of the model proposed, based on the explanatory variables introduced, as well as the supremacy of random forests over logistic regression.

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